The cast of “Falsettos,” from left, are Seth Bolles, Justin Quackenbush, Mindy Bickford, John Jensen and Bill Bickford. (Missing are Christina Weakland and Karen Lefkoe.)

What makes “Falsettos,” a quirky Broadway musical concerned with homosexuality and American middle class Jewish family life, compelling is its authenticity and its sheer unexpectedness.

Town Hall Theater opened its own production Thursday that proved both entertaining and poignant, directed by Doug Anderson and featuring some top-notch Vermont actors. Remaining performances of the mixed professional and community theater production are tonight and Sunday.

“Falsettos” is actually the final two-thirds of a trio of Off-Broadway one-act plays, “March of the Falsettos” and “Falsettos,” with book by James Lapine and William Finn and music and lyrics by Finn. The two shows comprise the complete Broadway musical, which earned five Tony Award nominations, and won Best Book of a Musical and Best Original Score in 1992.

In the first act, Marvin has just left his wife Trina for another man, Whizzer, a seemingly superficial boy-toy. Trina feels at a loss and turns to Marvin’s psychiatrist, Mendel, for answers, and romance ensues. Through all of this, Trina and Marvin’s pre-teen son Jason is trying to find his place.

In the second act, two years later, it’s time for Jason’s bar mitzvah. Mendel and Trina are married; and Marvin, despite losing Whizzer, has come to a truce with his ex-wife over the anticipated coming-of-age celebration. New neighbors, a lesbian couple comprised of a doctor and a caterer, have entered the picture.

Into this soap opera of often humorous emotional strife comes the dark reality of AIDS – which deeply, touchingly and unexpectedly brings this family circle together.

The show authentically relates some of the complexities of today’s never-sure family life. The music, attractive but derivative — much of it feels very familiar — successfully conveys the story. More importantly, “Falsettos,” at least in this production, proved entertaining even when confronting some of the day’s darkest issues.

Town Hall Theater’s intimate production was particularly well cast and imaginatively directed and choreographed by Anderson, who is also Town Hall’s executive director. Expert musical direction by Tim Guiles, with his five-piece pit band, proved the bedrock of the production.

John Jensen gave real dimension to Marvin, from cad to deeply caring father and partner, quite convincingly. Mindy Bickford was equally dimensional as Trina, who faces a life turned completely upside down. Bill Bickford (Mindy’s husband) also proved convincing as the psychiatrist whose own feelings occasionally overcome his professionalism.

Seth Jolles did a particularly fine acting job as Jason, torn between his parents as well as childhood and adulthood. Justin Quackenbush proved authentic as Whizzer, who turns out to be not so superficial. Christina Weakland and Karen Lefkoe were convincing and effective as the lesbian neighbors.

All were able singers, but at different levels, with Jensen and Quackenbush proving outstanding. Still, to a one, all had trouble with intonation and vocal comfort before warming up.

The physical production was simple, imaginative and effective (though there were some minor sound problems at Thursday’s opening night performance). The novel set was by Anderson and Buck Sleeper, lighting by Matthew Stone and costumes by Mary Kay Dempewolff.

Town Hall Theater presents its own production of “Falsettos,” the William Finn-James Lapine Broadway musical, March 21-24 at the theater, 68 S. Pleasant St. in Middlebury. Remaining performances are at 8 p.m. today and Sunday. Tickets are $20; call 382-9222, or go online to www.townhalltheater.org.